This study will involve children being treated for UTIs and adults without UTIs. All of the children will continue their prescribed amoxicillin/cefaclor treatment. After 7 to 10 days of antibiotic treatment, the children will be assigned to receive either cranberry juice for 2 days or no additional treatment. Urine samples will be collected from all child participants before and after the administration of cranberry juice to examine the excretion of the antibiotics.